Both airsupport are hybrid in a way. With AC-130, u get a limited amount of ammo and hard sometimes when its a bad map. The upside it, it has a wide range and its basically a 1 hit kill with the 1st and 2nd wep. Chopper gunner takes more time to kill and and barely has any dmg splash. But u can fly around the map with more mobility than AC-130. Its fun to get either one of those air support
Chopper Gunner for everything else (easy to get people inside of buildings if you know where to shoot (exploding rounds)...shoot at air ventilation units to get the people on the top level in Scrapyard, etc).